New brake pads & pedal to the ground !

[WIMPUS]

Hi !

I've fitted new brake pads (mintex m1144) as the old ones where worn.
So installed the new ones and on the testdrive the pedal wasn't that firm  :-/
Even going to the floor  :o
If you pump several times the fronts lock up.

Been to my uncle to bleed the fronts good and no air in the system (eventually doing everything).
Still pedal to the floor :/

Now going to check if the pistons more freely.. but do think it's the MC that have failed somewhere   :-/ (only a new one from august or something ! )

No leaks what so ever, fluid level doesn't drop, pwda valve isn't leaking for once ....  :o  :B

Any idea's ?  :'(

[markcro]

Yep, sounds like the MBC to me. I had a similar fail symptoms 2 years ago after I rebuilt my brake calipers. I bought a new MBC but the issue was no different so I ended up pull apart the calipers again, bleeding and bleeding…………..a month later and a lot of cursing I eventually realised that the new MBC was faulty from the box! So it gave the same symptoms. Grrr!!!

[WIMPUS]

markcro wrote:

Yep, sounds like the MBC to me. I had a similar fail symptoms 2 years ago after I rebuilt my brake calipers. I bought a new MBC but the issue was no different so I ended up pull apart the calipers again, bleeding and bleeding…………..a month later and a lot of cursing I eventually realised that the new MBC was faulty from the box! So it gave the same symptoms. Grrr!!!

My mc has been working from august 2014 until now...
So strange it should fail now.

but found a leaky t-piece at the back, hopefully that should be it ...
Just need to do a testdrive now  :)

[WIMPUS]

And still pedal to the ground !
Fed up with it for today, going to see if the pistons move freely and if that doesn't do anything ..... time to get the mc off ! :-/

[markcro]

My MBC was 100% as well until it failed as well. I reckon that when I bled the system the cylinder bore was full of crap from over the years and the seal failed when I pumped the pedal the full sweep as it went over all the crap.
But was was weirder was that the brand new one was faulty as well! I ended up rebuilding the original one and using that again.

[WIMPUS]

markcro wrote:

My MBC was 100% as well until it failed as well. I reckon that when I bled the system the cylinder bore was full of crap from over the years and the seal failed when I pumped the pedal the full sweep as it went over all the crap.
But was was weirder was that the brand new one was faulty as well! I ended up rebuilding the original one and using that again.

it's strange that the new mc has worked good for 8 months, my original had scoring inside :/
Got 2 other originals, but both are also not repairable..

Just pitted a new seal kit to my mc, couldn't see anything wrong with it .. will see how it goes !  :o

[markcro]

Let us know how you get on. I feel you pain! I chased my tail for about 2 months with mine. Grrr!!

[lancepar]

Not tried this myself.

Bikers have said holding back the lever to the bars with  a restraint of some type, nylon tie, and leaving overnight results in trapped air migrating back to the reservoir. So how about try wedging the brake pedal to the floor with a brace from somewhere like the seat frame or dash frame, 24hours?

I know that on my bike the position of the reservoir needs to be higher than the banjo on the end of the cylinder to get all the air out.

8)

[Richard B]

Take the pipe off your master cylinder and block it off with a bolt or some other way.

Then see if the cylinder will hold pressure. Sounds like when you pushed the pistons back some crap went up and damaged the seal. A reseal kit may well resolve the problem , although check the bore for scoring.

[WIMPUS]

Richard_B wrote:

Take the pipe off your master cylinder and block it off with a bolt or some other way.

Then see if the cylinder will hold pressure. Sounds like when you pushed the pistons back some crap went up and damaged the seal. A reseal kit may well resolve the problem , although check the bore for scoring.

Just rebuilded the master .. still not good :/

Going to try and do your test to see if the master is holding pressure  :)

[WIMPUS]

Like Richard said i got 2 bolts into the outlets .. rock solid pedal and not going deeper after time !

Also tested the pwda valve this way, again good pedal... so the problem is deeper ...  :-/

[heraldcoupe]

Are you using silicone fluid?

Cheers,
Bill.

[Velocita Rosso]

Wim...take the mc top off and get someone to pump the pedal and see if any bubbles come into the reservoir

[WIMPUS]

heraldcoupe wrote:

Are you using silicone fluid?

Cheers,
Bill.

Dot 4

[WIMPUS]

michael_charlton wrote:

Wim...take the mc top off and get someone to pump the pedal and see if any bubbles come into the reservoir

I can do that all by myself as i can pump and look at the reservoir  :P

But NO !, no bubbles when i pump  :-/

I also damaged my door as there where 2 drops of fluid on it .... hating brakes and brake fluid so much right now (angry)

[JensH]

How much of your braking system did you replace when you did your resto?
Could there be some dirt, petrol, white spirit, alcohol in old brake lines?

What brand of brake fluid do you use?

[WIMPUS]

JensH wrote:

How much of your braking system did you replace when you did your resto?
Could there be some dirt, petrol, white spirit, alcohol in old brake lines?

What brand of brake fluid do you use?

It got new pistons, seals & bleed nipple at the front.
At the rear drums every part on the inside is new exept the drums themself and the adjusters.
Brake master is new , pwda is re-sealed as you can't get that new, all new cunifer/copper brake lines from canley classics and also new flexi's front and rear.

So nearly everything from the brakes are new !

[markcro]

4526 wrote:

I also damaged my door as there where 2 drops of fluid on it .... hating brakes and brake fluid so much right now (angry)

Ah no way!  :-/  Again I feel you pain. When I was replacing the old MBC with a brand new one I decided to respray the whole bulk head. Took it down to metal, undercoat, multiple top coats and two coats of clear lacquer. It's looked great! :-)  But then with the new MBC being faulty and me being totally impatient as I was so p1ssed off, fluid destroyed the bulk head... :-(

Anyway stick at it and good luck. It does no harm to take a break and go back at it with fresh head.

[WIMPUS]

markcro wrote:

Ah no way!  :-/  Again I feel you pain. When I was replacing the old MBC with a brand new one I decided to respray the whole bulk head. Took it down to metal, undercoat, multiple top coats and two coats of clear lacquer. It's looked great! :-)  But then with the new MBC being faulty and me being totally impatient as I was so p1ssed off, fluid destroyed the bulk head... :-(

Anyway stick at it and good luck. It does no harm to take a break and go back at it with fresh head.

Well the bulkhead was flooded like 15min ago with brake fluid, forgot to tighten an union... starting to making stupid mistakes  :-/  :o
I got loads of water over the bulkhead, sprayed an heavy degreaser on to it and more water.. seems paint damage is minimal (already needed some touch ups from brake fluid damage..

The bulkhead i don't mind that much.. but that door  :-/
But then again it's the door that is fitting bad and i do have another door for that side, just need test fitting, a bit bodywork & paint... :B

[WIMPUS]

Checked the flexi hoses and they are fine, pumped the pedal to see how much was coming out of the brake line... not much !

So going to take the master off, then put some compressed air on the lines to make sure they are not blocked and check the master once more ... hopefully ... !

And i'm thinking of getting the pwda valve off again while i'm at it and put the new EPDM O-rings in it, otherwise next leaky job is that again (seems the regular o-rings can't cope with brake fluid, but at the time didn't have EPDM ones, so put again regular ones in it)

:o :o

Going a little mad ... nearly wanted to poor brake fluid over the whole car this afternoon  :B

[WIMPUS]

Going to blow the line through tomorrow, as it was a bit late to get the compressor on today.
A friend came by with his Spit, so that slowed work a bit down.

Got the master off again, got it apart again and could see one seal that wasn't that good ..
So installed another one there.
Got it back together and tested it in the garden... seems to work, but the real test will be tomorrow !

Also got the pwda off .. seems it was time to rebuild that also !  :B
Last time it was leaking i still didn't have the right seals, so got again usual rubber ones.

But now i got EPDM rubber one, so they will last a lot longer then a few months  :)

Here are some pics of the PWDA rebuild

the pic with the 3 seals: first o-ring on the left  it the usual rubber one that came out, middle o-ring was the original ones as the 1st one !
And the right side o-ring is the epdm one  :)

[Nick Moore]

Wim, you're turning into our tandem circuit brake guru! Where did you get the new PDWA seals?

[WIMPUS]

Nick_Moore wrote:

Wim, you're turning into our tandem circuit brake guru! Where did you get the new PDWA seals?

Got to a old school hydraulic place a few months ago ( dirt laying everywhere, pile of paper on the desks and a owner that was smoking like hell....i arrived the right place !  :P ).
He ordered them and the morning after i got them, they do fit very well.

[WIMPUS]

Tandem guru you say ?  :B

Got my original in the shed somewhere also, so got 4 !

[Saltddirk]

4526 wrote:

  :-/

I also damaged my door as there where 2 drops of fluid on it .... hating brakes and brake fluid so much right now (angry)

Who need Brakes? they only slow you down!
:)
D